This invention relates to an improved method of incorporating multifilament strands of carbon fibers into an aqueous hardenable hydraulic cementitious matrix which can be set to produce a carbon fiber-reinforced cementitious structure having improved flexural strength. More particularly, this invention relates to the preparation of a carbon fiber-reinforced structure having improved flexural strength from an aqueous hardenable hydraulic cementitious matrix containing multifilament strands of carbon fibers which have been treated with a hydrophobic resin system prior to being incorporated into the cementitious matrix.
Multifilament strands of carbon fibers have heretofore been employed to reinforce cement in an effort to increase the flexural strength of such cement. However, because of poor bonding between the filaments of the strands, and between the filaments of such strands and the cement, little or no improvement in the strength of the cement was attained by the addition of these fiber strands.